The present invention relates to an image forming apparatus having a function of printing without margin that forms an image by transferring a toner image onto an imaging area and a margin of a paper sheet.
Among image forming apparatus are there ones having a function of printing without margin that forms an image onto an imaging area and a margin of a paper sheet, as well as ones forming an image onto an imaging area of a paper sheet leaving a margin blank.
An image forming apparatus according to the electrophotography method forms an image onto a paper sheet through an imaging process in which a toner image is formed on a surface of an image bearing member, a transfer process in which the toner image is transferred from the surface of the image bearing member onto the paper sheet, and a fixing process in which the toner image transferred is fixed on the paper sheet by heating and pressing. Among methods for realizing the function of printing without margin in such an image forming apparatus is there one method that forms a toner image wider than a width of the paper sheet in the imaging process and transfers the image onto the margin of the paper sheet in the transfer process (for example, refer to Japanese Patent Unexamined Publication No. 2009-169106 bulletin). However, because the toner image is formed wider than the width of the paper sheet in the imaging process, the toner that has not been transferred onto the paper sheet is scattered within the interior of the image forming apparatus and thus sticks to the paper sheet, thereby causing stains on the paper sheet. So that it is necessary to collect the scattered toner after the transfer process.
Therefore, it is conceivable to collect the scattered toner after the transfer process by providing an adsorption member that is given an electric potential difference in relation to the toner, thereby causing the toner scattered onto the surface of the adsorption member to stick to the surface thereof, and then to remove the toner from the surface of the adsorption member. Now, among methods for removing the toner from the surface of the adsorption member is there a web cleaning that removes the toner from the surface of the adsorption member by causing a belt-shaped cleaning member to be brought into contact with the surface of the adsorption member and then winding the cleaning member.
However, the amount of the toner sticking to the surface of the adsorption member varies depending on whether the function of printing without margin is used or not.
Therefore, in the case where the function of printing without margin is not used, carrying out the web cleaning in such a manner as to meet a need for the case where the function of printing without margin is used results in winding the cleaning member that is not dirty, which means wasting the cleaning member. Contrariwise, in the case where the function of printing without margin is used, carrying out the web cleaning in such a manner as to meet a need for the case where the function of printing without margin is not used means nothing other than trying to remove the toner on the surface of the adsorption member using a dirty cleaning member, and thus it is impossible to collect the scattered toner.
The present invention is directed to providing an image forming apparatus according to the electrophotography method that makes it possible, in web cleaning, to pertinently use a cleaning member depending on whether a function of printing without margin is used or not, and to surely collect a toner causing stains on a paper sheet.